The present invention relates to a method for preparing a SiC whisker-reinforced composite material and, more particularly, to a method for preparing a high performance composite material by reinforcing a matrix material such as a metal, an alloy or a plastic with SiC whiskers.
SiC whiskers have high strength, elastic modulus, heat resistance and chemical stability, and also have excellent wetting properties with a matrix material. They have therefore been regarded as a most promising reinforcing material for metals and plastics. However, they have not yet been used as a reinforcing material for metals or plastics in a practical sense. The major technical factor which has prevented such use is the difficulty in achieving a uniform mixture and dispersion of SiC whiskers in a matrix material. SiC whiskers are prepared by subjecting a mixture of an SiO.sub.2 -containing powder with a carbonaceous material to a gas-phase reaction in an inert atmosphere within a temperature range of 1,400.degree. to 2,000.degree. C. However, the reaction product of this process has a cake-like structural form in which dense groups of microscopic SiC whiskers are entangled with each other in a random manner and hard to separate. A difficulty thus arises in uniformly dispersing such SiC whiskers in a matrix material.
For example, when the powder metallurgy method, as proposed in U.K. Pat. No. 1590728, is adopted for the SiC whiskers, a complex disintegration step is required to allow their uniform dispersion in the matrix material. Furthermore, since these SiC whiskers are extremely short, the conventional composite method for long fibers such as carbon fibers may not be adopted.